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Magnetic materials used for making permanent magnets (P) and magnets in a transformer (T) have different properties. Which property best matches for the type of magnet required? (1) T : Large retentivity, small coercivity (2) P : Small retentivity, large coercivity (3) T : Large retentivity, large coercivity (4) P : Large retentivity, large coercivity

1. T : Large retentivity, small coercivity
2. P : Small retentivity, large coercivity
3. T : Large retentivity, large coercivity
4. P : Large retentivity, large coercivity

Correct answer: P : Small retentivity, large coercivity

Solution

Permanent magnets require materials that can maintain their magnetization over time, which is characterized by large coercivity and small retentivity, allowing them to resist demagnetization while not needing to hold a strong magnetic field. In contrast, transformer magnets need materials that can easily magnetize and demagnetize, which is why they have low coercivity and high retentivity.

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